Solid propellant charge for combined rocket-ram-jet engines and process for making the same

ABSTRACT

A SOLID PROPELLENT CHARGE FOR COMBINED ROCKET-RAM-JET ENGINES CONTAINS A COMBINATION OF COMPOUNDS CAPABLE OF YIELDING UPON COMBUSTION AN EXTREMELY HIGH PERCENTAGE OF HYDROGEN AND A HIGH PERCENTAGE OF NITROGEN, BOTH CALCULATED ON THE CARBON PRESENT, SAID NITROGEN-CONTAINING COMPOUND HAVING CYANO- OR HYDRAZINE GROUPS CAPABLE OF RELEASING HIGH ENERGY, SAID COMBINATION ALSO INCLUDING AN OXIDIZER IN AN AMOUNT INSUFFECIENT FOR COMPLETE COMBUSTION. THE PROPELLENT CHARGE HAS NOT ONLY AN UNUSUALLY HIGH EFFECTIVENESS, BUT EXHIBITS AMONG OTHERS THE ADVANTAGE THAT DURING THE ROCKET PHASE NO CARBON WILL BE DEPOSITED AS SOOT, INCLUDING OTHER COMBUSTIBLE RESIDUES. THE INVENTION ALSO DISCLOSES A PROCESS FOR PRODUCING THE PROPELLANT CHARGE.

3,697,339 SOLID PROPELLANT CHARGE FOR COMBINED ROCKET-RAM-JET ENGINES AND PROCESS FOR MAKING THE SAME Paula Sarten, Munich, and Winfried Mair, Riemerling,

Germany, assignors to Messerschmitt-Bolkow Gesellschaft mit beschrankter Haftung, Ottobrunu, near Munich, Germany No Drawing. Filed Ian. 16, 1969, Ser. No. 791,802 Claims priority, application Germany, June 20, 1968, P 16 46 311.9 Int. Cl. (10Gb l1 U.S.. Cl. 149-19 9 Claims ABSTRACT OF THE DISCLOSURE A solid propellant charge for combined rocket-ram-jet engines contains a combination of compounds capable of yielding upon combustion an extremely high percentage of hydrogen and a high percentage of nitrogen, both calculated on the carbon present, said nitrogen-containing compound having cyanoor hydrazine groups capable of releasing high energy, said combination also including an oxidizer in an amount insutficient for complete combustion. The propellant charge has not only an unusually high efiectiveness, but exhibits among others the advantage that during the rocket phase no carbon will be deposited as soot, including other combustible residues. The invention also discloses a process for producing the propellant charge.

SUMMARY OF THE INVENTION The invention relates to solid propellants for combined rocket-ram-jet engines and a process for making the same. Such propellants have to satisfy stringent and extreme requirements. This is so because the incomplete combustion of the propellant during the rocket phase should result in the formation of gases that are rich in hydrogen or readily combustible low molecular saturated hydrocarbons and/or nitrogen compounds so that during the subsequent ram-jet operation reactive gases can be generated with the oxygen of the air which insure and yield high effectiveness and large specific output.

It is a further requirement that the combustible gases have such a high temperature that combustion will proceed and be maintained smoothly and effectively. Moreover, during the rocket phase, no carbon or soot should be deposited which could include combustible residues. These would, on the one hand, lower the temperature of the thrust flow during the rocket phase and, on the other hand, they would be incapable of reacting with air oxygen during the ram jet operation.

A solid propellant charge of the type here contemplated should therefore yield combustible substances, primarily hydrogen, upon combustion or decomposition with the oxygen of the air. The solid propellant charges used up to now, which are based on polybutadiene, or epoxy resins modified with natural resins based on terpenes, and the like, do not meet the requirements, or only meet them insufiiciently, even when various additives are used, such as ferrocene.

It is an object of the present invention to overcome the shortcomings of the solid propellant charges hitherto in use.

It is another object of the invention to provide a propellant charge which will yield during the rocket phase upon incomplete combustion, gases rich in hydrogen or readily combustible, low molecular hydrocarbons or nitrogen compounds, and which will generate reactive gases with the oxygen of the air during the ram jet operation, so as to insure a high effectiveness of the propellant.

States -Patent O 3,697,339 Patented Oct. 10, 1972 It is also an object of the invention to provide a process for producing the solid propellant charges according to the invention.

Other objects and advantages of the invention will become apparent from the following detailed description.

These objects are accomplished according to the invention by using as a base substance for the solid propellant charge for combined rocket-ram-jet engines, compounds poor in carbon and, at the same time, very rich in hydrogen, containing a high percentage of a nitrogen compound capable of releasing high energy nitrogen being in the'form of cyanoor hydrazine groups, and/ or other high energy additives, while at the same time providing an amount of an oxidizer insutficient for complete combustion, preferably of the type of a perchlorate. 'In spite of the incomplete combustion and due to the exothermic disintegration of the combustible ingredients, solid propellant charges of the type described will yield to the energy released during the rocket phase a propellant gas of high effectiveness having the above-mentioned desirable properties, the gas being then completely burned by the oxygen of the air during the ram jet operation and generating a maximum thrust action. Due to the insufficient oxidant, such as NH CIO4, being present in the rocket stage, and the extremely high percentage in hydrogen in the propellant moiety, it is possible to prepare for the ram jet engine a reactive gas mixture readily combustible with the oxygen of the air, the gas mixture being in the form of a mixture of nitrogen and hydrogen, and of various combustible carbon derivatives, of ammonia and the like decomposition residues with an ignition range within the ram jet operation.

In the following, a number of ingredients useful for the propellant combinations according to the invention will be listed:

4-aminodihydrazino-1,2,4-triazol 4-aminodihydrazino-1,2,4-triazolehydrocarbonate 4aminodihydrazino-1 ,2,4-triazolecarbonate 4-aminodihydrazino-1,2,4-triazolethiocyanate 4-aminodihydrazino-1,2,44riazolecyanide Triaminoguanidine Triaminoguanidinehydrocarbonate Triaminoguanidinecarbonate Triaminoguanidinehydrorhodanide Triaminoguanidinerhodanide Tn'aminoguanidinecyanide An addition of dihydrazinodicyanodiimine C H N causes a corresponding increase in the combustion temperature in the rocket phase. Other possible additives are powdered metals, e.g.

Be, Mg, Al, B, Zr, etc.

Hydrides of Li, Na, Be, K, etc.

Alanates and boranates of Li, Na, K, Be, etc.

Alkyls of Li, Na, K, Be, Al, Mg, Zn, etc.

Colloids of Li, Na, K, etc.

Ferrocenes, nickeloor cobaltocenes, etc., and other plasticizers and catalysts and/or surfactants.

The invention will now be more fully described with reference to a number of examples which are given below by way of illustration, but not of limitation. Parts are by weight.

EXAMPLE 1 About 72 parts of 4-aminodihydrazino-1,2,4-triazolrhodanide About 20 parts of Mg powder About 8 parts of binder About 650 parts of NH ClO About l-5 parts of various additives.

3 EXAMPLE 2 About 67.5 parts of 4-aminodihydrazino-1,2,4-triazolcyanide About 25.0 parts of NaAlH -About 7.5 parts of binder About 600 parts of NH ClO About 1-5 parts of various additives.

EXAMPLE 3 About 62 parts of 4-aminodihydrazino -1,2,4-triazolcyanide About 20 parts of Mg powder About '8 parts of binder About 600 parts of NH ClO About 1-'5 parts of various additives.

EXAMPLE 4 About 75 parts of triaminoguanidinecyanide About 20 parts of dihydrazinodicyanodiimine About 15 parts of binder About 650 parts of NH ClO About 1-5 parts of various additives.

EXAMPLE 5 About 75 parts of triaminoguanidinecyanide About -25 parts of NaAlH About 8 parts of binder About 650 parts of NH ClO About 1-5 parts of various additives.

The various additives mentioned in the examples may be known plasticizers, catalysts and hardening agents.

As binders, polymers used heretofore in compounding the charges, are satisfactory. Thus polybutadienes, epoxy resins, and similar polymers may be used while they are in the viscous or liquid state of prepolymerization. The use of the binders is explained more fully in the following example relating to the process of making the propellant charges according to the invention.

EXAMPLE 6 In preparing the solid propellant charge, the indicated amount of one of the combustible compounds of Examples 1-5 is mixed with the binder which is in a viscous state of prepolymerization. The compound is thoroughly agitated in the binder until a completely homogeneous mixture is obtained. We then add the oxidizer, NH ClO and continue homogenization of the mass. Subsequently, some of the additives of metallic nature or a plasticizer or catalyst may be introduced under nitrogen gas and kneaded into the mass until complete homogenization has occurred.

For final hardening, the composition is then stored, With or without addition of a hardening agent, at room temperature or slightly elevated temperature for hours.

What is claimed is:

1. A solid propellant charge for combined rocket-ramjet engines comprising, in a small amount of a polymeric binder matrix, a compound selected from the group consisting of 4-aminodihydrazine-1,2,4-triazo1 4-aminodihydrazino-1,2,4-triazolehydrocarbonate 4-aminodihydrazino-1,2,4-triazolecarbonate 4-aminodihydrazino-1,2,4-triazolethiocyanate 4-aminodihydrazino-1,2,4-triazolecyanide triaminoguanidine triaminoguanidinehydrocarbonate triaminoguanidinecarbonate triaminoguanidinehydrorhodanide triaminoguanidinerhodanide triaminoguanidinecyanide and an inorganic oxidizer salt in an amount insufficient for complete combustion.

2. The propellant charge according to claim 1, further comprising dihydrazinodicyanodiimine.

3. A propellant charge according to claim 1, wherein the inorganic oxidizer salt is a perchlorate of ammonia or potassium.

4. A propellant charge according to claim 1, consisting essentially of:

about 72 parts by weight of 4-aminodihydrazino-1,2,4-

triazol or 4-aminodihydrazino-1,2,4-triazolrhodanide about 20 parts by weight of Mg powder about 8 parts by weight of binder about 650 parts by weight of NH ClO and about 1 to 5 parts by weight of various additives such as a copperchromite as catalyst, an amine as hardener and a modified terpene resin as plasticizer.

5. A propellant charge according to claim 1, consisting essentially of:

about 67.5 parts by weight of 4-aminodihydrazino-1,2,4-

triazolcyanide about 25 parts by weight of NaAlH about 7.5 parts by weight of binder about 600 parts by weight of 'NH CIO and about 1 to 5 parts by weight of various additives such as a copperchromite as catalyst, an amine as hardener and a modified terpene resin as plasticizer.

6. A propellant charge according to claim 1, consisting essentially of:

about 62 parts by weight of 4-aminodihydrazino-1,2,4-

triazolcyanide about 20 parts by weight of Mg powder about 8 parts by Weight of binder about 600 parts by weight of NH CIO and about 1 to 5 parts by weight of various additives such as a copperchromite as catalyst, an amine as hardener and a modified terpene resin as plasticizer.

7. A propellant charge according to claim 1, consisting essentially of about 75 parts by weight of triaminoguanidine or of triaminoguanidinecyanide about Q0 parts by weight of dihydrazinodicyanodinmne about 15 parts by weight of binder about 650 parts by weight of NH ClO and about 1 to 5 parts by weight of various additives such as a copperchromite as catalyst, an amine as hardener and a modified terpene resin as plasticizer.

8. A propellant charge according to claim 1, consisting essentially of:

about 75 parts by weight of triaminoguanidinecyanide about 25 parts by weight of NaAlI-L;

about 8 parts by weight of binder about 650 parts by Weight of NH ClO and about 1 to 5 parts by weight of various additives, such as a copperchromite as catalyst, an amine as hardener and a modified terpene resin as plasticizer.

9. A process for producing a solid propellant charge for combined rocket-ram-jet engines, which comprises the steps of incorporating at normal temperature into a viscous prepolymer of a polymeric binder a compound selected from the group consisting of:

4-aminodihydrazine-1,2,4-triazol 4-aminodihydrazino-1,2,4-hydrocarbonate 4-aminodihydrazino-1,2,4-carbonate 4-aminodihydrazin'o-1,2,4-thiocyanate 4-aminodihydrazino-1,2,4-cyanide triaminoguanidine triaminoguanidinehydrocarbonate triaminoguanidinehydrorhodanide triaminoguanidinerhodanide triaminoguanidinecyanide homogenizing the said binder and said compound, adding further a perchlorate as an oxidizer, kneading the same into the mixture, incorporating other additives of the nature of a catalyst and a plasticizer under nitrogen gas, further homogenizing the entire mass, and finally causing hardening of the so prepared propellant.

(References on following page) References Cited UNITED STATES PATENTS Graham 149-36 Jenkins et a1 149-36 Benzing 149-36 Jennings et a1 149-36 Takals 149-20 6 3,375,230 3/1968 Oja et a1. 149-20 3,397,186 8/ 1968 Torley et a1 149-20 CARL D. QUARFORTH, Primary Examiner 5 S. J. LECHERT, JR., Assistant Examiner US. Cl. X.R. 

